State of the art of performance evaluation methods for concentrating solar collectors

Abstract

Abstract. For the development and establishment of concentrating solar thermal collectors a reliable and comparable performance testing and evaluation is of great importance. To ensure a consistent performance testing in the area of lowtemperature collectors a widely accepted and commonly used international testing standard (ISO 9806:2013) is already available. In contrast to this, the standard ISO 9806:2013 has not completely penetrated the testing sector of concentrating collectors yet. On that account a detailed literature review has been performed on published testing procedures and evaluation methodologies as well as existing testing standards. The review summarizes characteristics of the different steady-state, quasi-dynamic and fully dynamic testing methods and presents current advancements, assets and drawbacks as well as limitations of the evaluation procedures. Little research is published in the area of (quasi-) dynamic testing of large solar collectors and fields. As a complementary a survey has been conducted focusing on currently implemented evaluation procedures in this particular field. Among the ten participants of the survey were project partners of relevant industry and research institutions within the European project STAGE-STE (Work package 11 -Linear focusing STE technologies). The survey addressed general aspects of the systems under test, as well as required process conditions and detailed characteristics of the evaluation procedures. In congruence with the literature review, the survey shows a similar tendency: the quasi-dynamic testing method according ISO 9806:2013 presents the most common and advanced evaluation procedure mainly used in the context of tracking concentrating collectors for the performance assessment of parabolic trough collectors operating with thermal oil or pressurized water. These common solar systems can be evaluated with minor adaptions to the testing standard. Evaluation procedures focused on in-situ measurements in solar fields or collectors are scarce and complex as well as an evaluation of linear Fresnel collectors or other systems operating with non-common heat transfer media like molten salt and direct steam. As those are still SolarPACES 2015

IEA SHC Task 49/IV - Deliverable A2.1 - Comparison of process heat collectors with respect to technical and economic conditions

“…The Solar Keymark is used in Europe and increasingly recognized worldwide. Besides ISO 9806, directly linked to the Solar Keymark database, other solar collector standards are available: For example ASHRAE 93-2003, applicable to non-tracking collectors or ASTM E 905-87 applicable to tracking collectors (Hofer A. et al 2015). Additional collector databases are available as well at other national or international certification entities such as the American Solar Rating and Certification Corporation (SRCC).…”

Improved in situ performance testing of line-concentrating solar collectors: Comprehensive uncertainty analysis for the selection of measurement instrumentation

“…Several research institutes and companies are currently investigating adequate testing and evaluation methods for line-concentrating collectors, pursuing different approaches of steady-state testing [2], quasi-dynamic testing [3] or dynamic testing [4,5]. A review on current testing procedures has jointly been published by experts within this working field (for an overview and details on the testing procedures, see Hofer et al [6]), revealing a lack of standardized, flexible and applicable testing procedures for concentrating solar collectors. Therefore, national and international standardization efforts (ISO TC 180, IEC TC 117, and AENOR) are being devoted to make performance evaluation for lineconcentrating collectors more comparable and reliable, which are considered to substantially contribute to the further development and market penetration of this emerging technology.…”

IEA SHC Task 49/IV - Deliverable A3.1 - Guideline on testing procedures for collectors used in solar process heat

“…A literature review has been conducted by Hofer et al (2015b) focusing on testing and evaluation procedures for tracking concentrating collectors. Figure 3 summarizes published evaluation methods in this context.…”